Phosphorus containing compounds and epoxy resins thereof

ABSTRACT

Phosphorous containing compounds, epoxy resins thereof, and laminate composite structures thereof. The phosphorus containing compounds may have a structure according to formula (I): 
                         
wherein, X is an aromatic hydrocarbon group having 6 to 30 carbon atoms or a bivalent linear or branched alkylene group of 1 to 8 carbon atoms; R A  is selected from an alkyl group having 1 to 6 carbon atoms, a phenyl group, a napthyl group, and an aromatic phenol group; w is an integer of 1 to 9; R 1 , R 2 , R 3 , and R 4  are independently selected from H, C 1 -C 10  alkyl, C 1 -C 10  alkoxy, and C 3 -C 10  cycloalkyl; R 5  is selected from the group consisting of C 1 -C 10  alkyl, C 1 -C 10  alkoxy, C 3 -C 10  cycloalkyl, and Ar 3 ; and Ar 1  and Ar 2  are independently selected.

FIELD OF THE DISCLOSURE

The instant disclosure is directed to phosphorous containing compounds,epoxy resins thereof, and laminate composite structures thereof.

BACKGROUND OF THE DISCLOSURE

Due to good resistance to solvents, excellent mechanical strength, andelectrically insulating properties, etc., epoxy resins are widely used.For example, epoxy resins are often applied to coating materials,electrically insulating materials, printed circuit laminated boards andelectronic packaging materials, construction and building materials,adhesives, and navigation technology. Epoxy resins, however, can havepoor thermal resistance and burn easily, which may set significantrestriction on the uses of such epoxy resins.

With the development of high-performance and networked signalcommunication equipment, in order to process a large number of signalsfor high-speed transmission, the operation signals are moving towardhigh speed and high frequency transmission. In order to achieve theabove object, the material of the printed circuit board of the signalcommunication device needs to have good dielectric capability (lowdielectric constant and low loss dissipation factor) to meet the needsof high frequency transmission of signals, and good heat resistance andmachinability to meet the reliability of printed circuit boards.

Therefore, with development of electronic technology, the industry hassought to improve flame retardant properties and thermal resistance ofepoxy resins. There has been a plurality of techniques available forimproving the flame retardant properties of epoxy resins, the mostcommon one of which is to introduce a flame retardant into an epoxyresin. Often, a halogen-containing flame retardant is used. Althoughhalogens are effective for retarding flames, they can produce erosiveand toxic hydrogen halide gases. Additionally, the use of halogenationof epoxy resins sometimes leads to environmental concerns.

SUMMARY OF THE DISCLOSURE

Aspects of the disclosure relate to phosphorous containing compounds,epoxy resins thereof, and laminate composite structures thereof.Additional aspects of the disclosure relate to methods for producingsuch phosphorous containing compounds and epoxy resins. The phosphorouscontaining compounds may be used to form flame retardant phosphorouscontaining resins, such as epoxy resins, as well as server as a hardenerfor such resins.

According to a first aspect of the disclosure, provided is phosphorouscontaining compounds having a structure represented by formula (I),provided below:

wherein,

-   -   X is an aromatic hydrocarbon group having 6 to 30 carbon atoms        or a bivalent linear or branched alkylene group of 1 to 8 carbon        atoms,    -   R^(A) is selected from an alkyl group having 1 to 6 carbon        atoms, a phenyl group, a napthyl group, and an aromatic phenol        group,    -   w is an integer of 1 to 9,    -   R₁, R₂, R₃, and R₄ are independently selected from H, C₁-C₁₀        alkyl, C₁-C₁₀ alkoxy, and C₃-C₁₀ cycloalkyl,    -   R₅ is selected from the group consisting of C₁-C₁₀ alkyl, C₁-C₁₀        alkoxy, C₃-C₁₀ cycloalkyl, and Ar₃, and    -   Ar₁ and Ar₂ are independently selected from the following        structure:

wherein Ar₃ is selected from the following structures:

wherein:

-   -   R₆ and R₇ are independently selected from the group consisting        of H, C₁-C₁₀ alkyl group, C₁-C₁₀ alkoxy, and a cyclic alkyl        group having 3-10 carbon atoms,    -   m and n are independently an integer from 0 to 3, and m plus n        is less than 5.    -   R₈ is absent or is selected from the group consisting of —CH₂—,        —(CH₃)₂C—, —CO—, —SO₂—, and —O—, and    -   R₉ is absent or is —(CH₂)_(p), wherein p is an integer from 1 to        20, and z is 1.

The X group may be a bivalent aromatic hydrocarbon group containing from6 to 30 carbon atoms, a bivalent linear or branched alkylene groupcontaining from 1 to 8 carbon atoms, or a bivalent linear or branchedalkenylene group containing from 2 to 8 carbon atoms. In some instances,the X group is an aromatic hydrocarbon group having 6 to 10 carbonatoms. In further instances, the X groups is an aromatic hydrocarbonhaving 6 to 8 carbon atoms. The aromatic hydrocarbon of X may beunsubstituted.

The R^(A) group may be an aromatic phenol group, such as those selectedfrom a phenol group, an o-cresol group, a m-cresol group, p-cresolgroup, an 1-naphthol group. Alternatively, the R^(A) group may be analkyl group having 1 to 4 carbon atoms. For example, the alkyl group ofR^(A) may have 2 carbon atoms or 1 carbon atom. Additionally oralternatively, the R^(A) group may be an unsubstituted alkyl group.

In some instances, the phosphorous containing compounds according toformula (I) have a structure wherein R₁, R₂, R₃, and R₄ are H; R₅ is amethyl; and Ar₁ and Ar₂ are phenylene groups. For example, thephosphorous containing compounds according to formula (I) may includethe following structure (Ia):

In at least one case, the phosphorous containing compounds according toformula (I), wherein R₁, R₂, R₃, and R₄ are H; R₅ is a methyl; Ar₁ andAr₂ are phenylene groups; X is an unsubstituted aromatic hydrocarbongroup; R^(A) is an alkyl group having a carbon atom.

According to a further aspect of the disclosure, provided is a curedepoxy resin comprising an epoxy and the phosphorus containingcompound(s) according to formula (I). The cured epoxy resin preferablyhas a glass transition temperature of greater than 170° C. For example,the glass transition temperature of the cured epoxy resin may be 180° C.or more, 190° C. or more, 200° C. or more. Additionally oralternatively, an epoxy resin cured with the phosphorus containingcompound(s) of the disclosure may have a dielectric constant of 3.0 orless as measured according to IPC-TM-650-2.5.5.13 at 10 GHz. The curedepoxy resin may also or alternatively have a dissipation factor of 0.014or less as measured according to IPC-TM-650-2.5.5.13 at 10 GHz.

In accordance with yet another aspect of the disclosure, a laminatecomposite structure is provided comprising (a) a glass fiber fabric, (b)an epoxy, (c) a copper foil, and (d) a phosphorus containing compoundaccording to formula (I). The laminate composite structure may have acured epoxy resin containing the phosphorous containing compound(s)according to formula (I), where R₁, R₂, R₃, and R₄ are H; R₅ is amethyl; and Ar₁ and Ar₂ are phenylene groups. In at least one case, thelaminate composite structure includes a cured epoxy resin containingphosphorous containing compound(s) wherein R₁, R₂, R₃, and R₄ are H; R₅is a methyl; Ar₁ and Ar₂ are phenylene groups; X is an unsubstitutedaromatic hydrocarbon group; R^(A) is an alkyl group having a carbon.

The laminate composite structure preferably has a dielectric constant of4.6 or less, 4.5 or less, 4.4 or less, or 4.3 or less as measuredaccording to IPC-TM-650-2.5.5.13 at 10 GHz. Additionally oralternatively, laminate composite structure may have a dissipationfactor of 0.015 or less, 0.014 or less, 0.013 or less, 0.012 or less,0.010 or less, or 0.009 or less as measured according toIPC-TM-650-2.5.5.13 at 10 GHz.

DETAILED DESCRIPTION OF THE DISCLOSURE

Aspects of the disclosure relate to phosphorous containing compounds,epoxy resins thereof, and laminate composite structures thereof. Theinventors discovered that phosphorus containing compounds for curing anepoxy resin could be improved by forming a compound containing DMPcompounds and replacing the hydroxyl groups with acyloxy groups(—O—(C═O)—R). Without being limited to any specific theory, theinventors believe that the phosphorous containing compounds of theinstant disclosure have reduced water absorption and improved dielectricproperties over curing agents with hydroxyl groups because such hydroxylgroups are suspected to produce strong polarities within the curedresin.

More specifically, the Inventor's discovered that epoxy resins curedwith certain phosphorous containing compounds, such as those producedfrom DMP and particular dicarboxylic acids and anhydrides, exhibitedimproved dielectric properties and thermal resistance while alsomaintaining a high level of flame retardancy. The improvements indielectric properties and thermal properties while maintaining and/orimprove the level of flame retardancy was unexpected.

According to a first aspect of the disclosure, provided is a phosphorouscompound having a structure represented by formula (I), provided below:

wherein,

-   -   X is an aromatic hydrocarbon group having 6 to 30 carbon atoms        or a bivalent linear or branched alkylene group of 1 to 8 carbon        atoms,    -   R^(A) is selected from an alkyl group having 1 to 6 carbon        atoms, a phenylene group, a napthyl group, and an aromatic        phenol group,    -   w is an integer of 1 to 9,    -   R₁, R₂, R₃, and R₄ are independently selected from H, C₁-C₁₀        alkyl, C₁-C₁₀ alkoxy, and C₃-C₁₀ cycloalkyl,    -   R₅ is selected from the group consisting of C₁-C₁₀ alkyl, C₁-C₁₀        alkoxy, C₃-C₁₀ cycloalkyl, and Ar₃, and    -   Ar₁ and Ar₂ are independently selected from the following        structure:

wherein Ar₃ is selected from the following structures:

wherein:

-   -   R₆ and R₇ are independently selected from the group consisting        of H, C₁-C₁₀ alkyl group, C₁-C₁₀ alkoxy, and a cyclic alkyl        group having 3-10 carbon atoms,    -   m and n are independently an integer from 0 to 3, and m plus n        is less than 5,    -   R₈ is absent or is selected from the group consisting of —CH₂—,        —(CH₃)₂C—, —CO—, —SO₂—, and —O—, and    -   R₉ is absent or is —(CH₂)_(p), wherein p is an integer from 1 to        20, and z is 1.

The X group is typically an aromatic hydrocarbon group having 6 to 30carbon atoms or a bivalent linear or branched alkylene group of 1 to 8carbon atoms. Preferably, the X group is an aromatic hydrocarbon grouphaving 6 to 20 carbon atoms, e.g., 6 to 18 carbon atoms, 6 to 16 carbonatoms, 6 to 14 carbon atoms, 6 to 12 carbon atoms, or 6 to 10 carbonatoms. In some instances, the X group is an aromatic hydrocarbon grouphaving 6 to 8 carbon atoms. Alternatively, the X group may be a bivalentlinear or branched alkylene group having 7 carbon atoms, 6 carbon atoms,5 carbon atoms, 4 carbon atoms, 3 carbon atoms, 2 carbon atoms, 1 carbonatom, or any range therebetween. Although the X group is preferablyunsubstituted, the aromatic group may be substituted in variousinstances. In some cases, the X group may have a structure correspondingisophthalic acid, terephthalic acid, dibenzoic acid,naphthalenedicarboxylic acids, 4,4′-diphenylenedicarboxylic acid,bis(p-carboxyphenyl)methane acid, ethylenebis(p-benzoic acid),1,4-tetramethylenebis(p-oxybenzoic acid), ethylenebis(paraoxybenzoicacid), 1,3-trimethylene bis(p-oxybenzoic acid), isophthaloyl dichloride,terephthaloyl dichloride, malonyl dichloride, or a derivative thereof.For example, the X group may be formed by reacting one of the foregoingacids with additional compound, as further discussed below, to form thephosphorous containing compound of the instant disclosure.

Typically, the R^(A) group is an aromatic phenol group, such as thoseselected from a phenol group, an o-cresol group, a m-cresol group, ap-cresol group, an 1-naphthol group. The aromatic phenol group of R^(A)may have 1 to 10 carbon atoms including, e.g., 1 to 8 carbon atoms, 1 to7 carbon atoms, or 1 to 6 carbon atoms. In some instances, the R^(A)group may be an alkyl group having 1 to 10 carbon atoms. For example,the R^(A) group may be an alkyl group including 1 to 6 carbon atoms, 1to 4 carbon atoms, 1 to 3 carbon atoms, etc. In a preferred example, thealkyl group of R^(A) has 2 carbon atoms or 1 carbon atom. Additionallyor alternatively, the R^(A) group may be an aromatic group or an alkylgroup that is substituted or unsubstituted.

R₁, R₂, R₃, and R₄ are generally independently selected from H, C₁-C₁₀alkyl, C₁-C₁₀ alkoxy, and C₃-C₁₀ cycloalkyl. Although the groups of R₁,R₂, R₃, and R₄ may each be independently selected to have a differentstructure, in some cases R₁, R₂, R₃, and R₄ may be selected such thattwo of the groups, three of the groups, or all of the groups have thesame structure. R₁, R₂, R₃, and R₄ may be independently selected fromhydrogen, C₁-C₄ unsubstituted alkyl, C₁-C₄ substituted alkyl, C₁-C₁₀unsubstituted alkoxy, C₁-C₁₀ substituted alkoxy, C₃-C₁₀ unsubstitutedcycloalkyl, and C₃-C₁₀ substituted cycloalkyl. For instance, R₁, R₂, R₃,and R₄ may be selected from substituted or unsubstituted alkyl groupshaving 10 carbon atoms, 9 carbon atoms, 8 carbon atoms, 7 carbon atoms,6 carbon atoms, 5 carbon atoms, 4 carbon atoms, 3 carbon atoms, 2 carbonatoms, 1 carbon atom, or any range formed therefrom. R₁, R₂, R₃, and R₄may be selected from a C₁-C₁₀ alkoxy groups selected from substituted orunsubstituted alkoxy groups having 10 carbon atoms, 9 carbon atoms, 8carbon atoms, 7 carbon atoms, 6 carbon atoms, 5 carbon atoms, 4 carbonatoms, 3 carbon atoms, 2 carbon atoms, 1 carbon atom, or any rangeformed therefrom. Additionally or alternatively, R₁, R₂, R₃, and R₄ maybe selected from C₃-C₁₀ cycloalkyl groups that are substituted orunsubstituted. In some cases, the C₃-C₁₀ cycloalkyl group of R₅ includes10 carbon atoms, 9 carbon atoms, 8 carbon atoms, 7 carbon atoms, 6carbon atoms, 5 carbon atoms, 4 carbon atoms, 3 carbon atoms or anyrange formed therefrom. In some embodiments, R₁, R₂, R₃, and R₄ areindependently selected from the group consisting of hydrogen, methyl,ethyl, isopropyl, n-propyl, n-butyl, and tert-butyl. In someembodiments, R₁, R₂, R₃, and R₄ are hydrogen.

R₅ is typically independently selected from the group consisting ofC₁-C₁₀ alkyl, C₁-C₁₀ alkoxy, C₃-C₁₀ cycloalkyl, and Ar₃. R₅ may beselected from C₁-C₁₀ alkyl groups that are substituted or unsubstituted.For instance, R₅ may be selected from substituted or unsubstituted alkylgroups having 10 carbon atoms, 9 carbon atoms, 8 carbon atoms, 7 carbonatoms, 6 carbon atoms, 5 carbon atoms, 4 carbon atoms, 3 carbon atoms, 2carbon atoms, 1 carbon atom, or any range formed therefrom. R₅ may beselected from a C₁-C₁₀ alkoxy groups selected from substituted orunsubstituted alkoxy groups having 10 carbon atoms, 9 carbon atoms, 8carbon atoms, 7 carbon atoms, 6 carbon atoms, 5 carbon atoms, 4 carbonatoms, 3 carbon atoms, 2 carbon atoms, 1 carbon atom, or any rangeformed therefrom. Additionally or alternatively, R₅ may be selected fromC₃-C₁₀ cycloalkyl groups that are substituted or unsubstituted. In somecases, the C₃-C₁₀ cycloalkyl group of R₅ includes 10 carbon atoms, 9carbon atoms, 8 carbon atoms, 7 carbon atoms, 6 carbon atoms, 5 carbonatoms, 4 carbon atoms, 3 carbon atoms or any range formed therefrom. R₅may also be selected from groups having a structure according to Ar₃, asshown below:

Typically, the groups of Ar₁ and Ar₂ are independently selected from thefollowing structures:

Although Ar₁ and Ar₂ may be groups having different structures, in somecases Ar₁ and Ar₂ are groups having the same structure. R₆ and R₇ areindependently selected from the group consisting of H, C₁-C₁₀ alkylgroup, C₁-C₁₀ alkoxy, and a cyclic alkyl group having 3-10 carbon atoms.In some instances, however, the groups of R₆ and R₇ may be the same. TheR₆ and R₇ may be selected from substituted or unsubstituted alkyl groupshaving 1 to 10 carbon atoms. For instance, R₆ and R₇ may be selectedfrom substituted or unsubstituted alkyl groups having 10 carbon atoms, 9carbon atoms, 8 carbon atoms, 7 carbon atoms, 6 carbon atoms, 5 carbonatoms, 4 carbon atoms, 3 carbon atoms, 2 carbon atoms, 1 carbon atom, orany range formed therefrom. R₆ and R₇ may each be independently selectedfrom a C₁-C₁₀ alkoxy groups selected from substituted or unsubstitutedalkoxy groups having 10 carbon atoms, 9 carbon atoms, 8 carbon atoms, 7carbon atoms, 6 carbon atoms, 5 carbon atoms, 4 carbon atoms, 3 carbonatoms, 2 carbon atoms, 1 carbon atom, or any range formed therefrom. R₆and R₇ may each be independently may be selected from C₃-C₁₀ cycloalkylgroups that are substituted or unsubstituted. In some cases, the C₃-C₁₀cycloalkyl group of R₅ includes 10 carbon atoms, 9 carbon atoms, 8carbon atoms, 7 carbon atoms, 6 carbon atoms, 5 carbon atoms, 4 carbonatoms, 3 carbon atoms or any range formed therefrom.

The repeating unit value (“w”) is typically an integer of 1 to 9, suchas 1, 2, 3, 4, 5, 6, 7, 8, or 9. Preferably, the w value ranges from 2to 9. The inventors discovered that when the w value is 10 or more, thephosphorous containing compound tends to exhibit precipitation duringcuring and the processability of epoxy resin becomes poor. To reduceprecipitation during curing, additional solvent (such as methyl ethylketone, “MEK”) may be used. However, the use of additional solvent alsoresults in a reduced viscosity for the epoxy resin. Thus, when the wvalue is 10 or more, the properties of the epoxy resin may be limited asa result of precipitation concerns and/or poor processability.Unexpectedly, however, the inventors discovered that when the w valueranges from 2 to 9, the processability of the epoxy resin issignificantly improved and precipitation is unlikely.

The phosphorous containing compounds may be substantially free of orfree of epoxide and/or oxirane groups. In some instances, thephosphorous containing compounds are substantially free of or free ofhydroxyl groups.

In at least one embodiment, the phosphorous containing compoundaccording to formula (I) has a structure wherein R₁, R₂, R₃, and R₄ areH; R₅ is a methyl; and Ar₁ and Ar₂ are phenylene groups, such that thephosphorous containing compound of formula (I) includes structure (Ia),below:

In at least one other embodiment, the phosphorous containing compoundhas a structure according to formula (II), provided below.

In accordance with another aspect of the disclosure, a method isprovided for producing the phosphorous containing compounds. The methodtypically includes reacting6-(1,1-bis(4-hydroxyphenyl)ethyl)dibenzo[c,e][1,2]oxaphosphinine 6-oxide(“DMP”) compounds with an acid anhydride and an acid or chloride. Theacid anhydride may be selected from acids anhydrides having a carbonchain of 1 to 6 carbon atoms. For example, the acid anhydride may beacetic anhydride, propionic anhydride, n-butyric anhydride, benzoicanhydride, trifluoroacetic anhydride, and/or3a-methyl-5,6-dihydro-4H-isobenzofuran-1,3-dione. Preferably, the acidanhydride is acetic anhydride.

The acid may be a dicarboxylic acid. Additionally or alternatively, theacid or chloride may be selected from isophthalic acid, terephthalicacid, dibenzoic acid, naphthalenedicarboxylic acids,4,4′-diphenylenedicarboxylic acid, bis(p-carboxyphenyl)methane acid,ethylenebis(p-benzoic acid), 1,4-tetramethylenebis(p-oxybenzoic acid),ethylenebis(paraoxybenzoic acid), 1,3-trimethylene bis(p-oxybenzoicacid), isophthaloyl dichloride, terephthaloyl dichloride, malonyldichloride, a salt thereof, a derivative thereof, and a combinationthereof. In at least one instance, the method includes reacting DMP withacetic anhydride and isophthalic acid to produce the phosphorouscontaining compounds of formula (I).

The DMP and the dicarboxylic acid and/or chloride may be in the mixturetogether at a molar ratio of DMP to dicarboxylic acid and/or chloride of2:1 to 10:8.9. For example, the molar ratio of DMP to dicarboxylic acidand/or chloride may be 1.9:1 to 10:8.9, 1.8:1 to 10:8.9, 1.7:1 to10:8.9, 1.6:1 to 10:8.9, or 1.5:1 to 10:8.9. Preferably, the DMP and thedicarboxylic acid and/or chloride may be mixed together in amounts suchthat the phosphorous containing compound of the disclosure has arepeating unit value (“w”) of 2 to 9, as discussed further above.

The mixture comprising the DMP compound, acid anhydride, and/or acidand/or chloride may be heated to promote a reaction between the DMPcompound, acid anhydride and/or the acid. For instance, the temperatureof the mixture may be raised to 30° C. or more, e.g., 40° C. or more,50° C. or more, 60° C. or more, 70° C. or more, 80° C. or more, 90° C.or more, 100° C. or more, 110° C. or more, 120° C. or more, 130° C. ormore, or 140° C. or more. The temperature may be maintained at theraised temperature for 1 hour (hr) or more, 2 hrs or more, 3 hrs ormore, 4 hrs or more, 5 hrs or more, 6 hrs or more, or 7 hrs or more.

The method may include removing acetic acid or other byproducts bydistillation. One of ordinary skill would be able to readily determinemethods and suitable equipment for removing the acetic acid bydistillation based on the disclosure herein. Although, the method mayinclude the removal of acetic acid by distillation, other means forremoving the acetic acid may be utilize without deviating from the scopeof the disclosure.

The compound of Formula (I) may have a phosphorus content of at least2%. In various embodiments, the compound of Formula (I) may have aphosphorus content of at least 2.3%, at least 2.5%, at least 3.0%, atleast 4.0%, at least 5.0%, or greater than 5.0%.

According to a further aspect of the disclosure, provided is an epoxyresin cured with the phosphorous containing compounds disclosed herein.The ideal equivalence ratio of the epoxy to the phosphorous containingcompounds of formula (I) is preferably from 1:1 to 1:3. In someinstances, the ideal equivalence ratio of the epoxy to the phosphorouscontaining compounds of formula (I) may be 1:1 to 1:2.8, 1:1 to 1:2.6,1:1 to 1:2.4, 1:1 to 1:2.2, 1:1 to 1:2, 1:1 to 1:1.8, 1:1 to 1:1.6, or1:1 to 1:1.5. Although all of the curing agent in the epoxy resin may bephosphorus containing compounds of formula (I), in some instances theforegoing amounts of curing agent comprise an additional curing agent.

The cured epoxy resin preferably has a glass transition temperature ofgreater than 180° C. For example, the glass transition temperature ofthe cured epoxy resin may be 182° C. or more, 184° C. or more, 186° C.or more, 188° C. or more, 190° C. or more, 192° C. or more, 194° C. ormore, 196° C. or more, 198° C. or more, or 200° C. or more.

Additionally or alternatively, an epoxy resin cured with the phosphoruscontaining compounds of the disclosure may have a dielectric constant of4.5 or less as measured according to IPC-TM-650-2.5.5.13 at 10 GHz. Forinstant, the dielectric constant of the cured epoxy resin may be 4.4 orless, 4.35 or less, or 4.3 or less, as measured according toIPC-TM-650-2.5.5.13 at 10 GHz. In some cases, the epoxy resin cured withthe phosphorus containing compounds may have a dielectric constant of3.4 or less, 3.3 or less, 3.2 or less, 3.1 or less, or 3.05 or less, 3.0or less, 2.9 or less, 2.8 or less, or 2.7 or less, as measured accordingto IPC-TM-650-2.5.5.13 at 10 GHz. The epoxy resin cured with thephosphorous containing compounds of the disclosure may also oralternatively have a dissipation factor of 0.014 or less as measuredaccording to IPC-TM-650-2.5.5.13 at 10 GHz. For example, the cured epoxyresin may have a dissipation factor of 0.011 or less, 0.0109 or less,0.0105 or less, 0.0100 or less, or 0.0097 or less, as measured accordingto IPC-TM-650-2.5.5.13 at 10 GHz.

In accordance with yet another aspect of the disclosure, a laminatecomposite structure is provided comprising glass fiber fabricimpregnated with a cured epoxy resin, the cured epoxy resin containingphosphorus containing compounds according to formula (I). The laminatecomposite structure may be produced by impregnating glass fiber with anepoxy resin and curing the epoxy resin with the phosphorous containingcompounds of the disclosure and, optionally, one or more additionalcuring agents. The cured epoxy impregnated fiber fabrics may be appliedto a substrate, such as a copper foil, circuit boards, circuitrycomponents, or other electrically conductive materials. The epoxyimpregnated fiber fabrics and substrate structure may be laminated toform a laminate composite structure.

In some instances, the laminate composite structure has a cured epoxyresin containing the phosphorous containing compounds according toformula (I), where R₁, R₂, R₃, and R₄ are H; R₅ is a methyl; and Ar₁ andAr₂ are phenylene groups. In at least one case, the laminate compositestructure includes a cured epoxy resin containing phosphorous containingcompounds according to formula (II), provided below.

The laminate composite structure comprising an epoxy resin cured with aphosphorous compound disclosed herein preferably has a dielectricconstant of 4.6 or less as measured according to IPC-TM-650-2.5.5.13 at10 GHz. For instance, the dielectric constant of the laminate compositestructure may be 4.4 or less, 4.35 or less, or 4.3 or less, as measuredaccording to IPC-TM-650-2.5.5.13 at 10 GHz.

The laminate composite structure comprising an epoxy resin cured with aphosphorous compound disclosed herein may also have a dissipation factorof 0.015 or less as measured according to IPC-TM-650-2.5.5.13 at 10 GHz.For example, the laminate composite structure may have a dissipationfactor of 0.014 or less, 0.011 or less, 0.0109 or less, 0.0105 or less,0.0100 or less, 0.0097 or less, as measured according toIPC-TM-650-2.5.5.13 at 10 GHz.

EXAMPLES

The following non-limiting examples are provided primarily for thepurposes of elucidating benefits and advantages achieved by aspects ofthe invention.

Example 1

Synthesis of DMP1

DMP 1 was prepared according to the following procedure for use in thefollowing examples. Specifically, 216.2 grams (“g”) (1 mole) of9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (“DOPO”), 470.5 g (5mole) of phenol, 136.2 g (1 mole) of 4′-hydroxyacetophenone, and 8.65 g(4 wt. %, based on the weight of DOPO) of p-toluenesulfonic acid weremixed and stirred in a 3000 ml three-necked flask reactor at roomtemperature in advance. The foregoing reactants were stirred constantlyat a temperature of 130° C. for 6 hours (“hrs”) to form a mixture, andthen the temperature of the mixture was cooled to room temperature. Thecooled mixture was separated to obtain the crude products, which werewashed with ethanol and then filtrated and dried. Aphosphorus-containing bisphenol product A1 (“DMP 1”) was obtained in theform of a white powder. The structure of DMP 1 is provided above.

Synthesis of DMP 2

DMP 2 was prepared by mixing and stirring 10.81 g (0.05 mole) of DOPO,36 g (0.25 mole) of 2-naphthol, 6.81 g (0.05 mole) of4′-Hydroxyacetophenone, and 0.432 g (4 wt % based on the Weight of DOPO)of p-toluene sulfonic acid in a 250 ml three-necked flask reactor atroom temperature. The reactants were stirred constantly at 130° C. for24 hours to form a mixture, and then the temperature of the mixture wascooled down to the room temperature. The crude products were separatedout from the cooled mixture and washed using ethanol and then filtratedand dried to obtain a white powder. The white powder was thephosphorus-containing compound A₂ (“DMP 2”).

The yield of the foregoing phosphorus-containing bisphenol was 85%, andthe melting point was 317° C. The measured value of the carbon,hydrogen, and oxygen element was 75.54%, 4.58%, and 13.56%, respectively(the theoretical value of C was 75.31%, 4.85% for H, 13.38% for O) byelement analysis.

Synthesis of DMP 3

DMP 3 was prepared by mixing and stirring 10.81 g (0.05 mole) of DOPO,36 g (0.25 mole) of 2-naphthol, 9.01 g (0.05 mole) of6-acetyl-2-naphthol, and 0.432 g (4 wt % based on the Weight of DOPO) ofp-toluene sulfonic acid in a 250 ml three-necked flask reactor at roomtemperature. The reactants were stirred constantly at 130° C. for 24hours to form a mixture, and then the temperature of the mixture wascooled down to the room temperature. The crude products were separatedout from the cooled mixture and washed with ethanol and then filtratedand dried to obtain a white powder. The white powder was thephosphorus-containing compound A3 (“DMP 3”), shown above.

The yield of the foregoing phosphorus-containing bisphenol was 80%, andthe melting point was 338° C. The measured value of the carbon,hydrogen, and oxygen element were 77.69%, 4.17%, and 12.25%,respectively (the theoretical value for C was 77.26%; 4.76% for H;12.11% for O) by element analysis.

Example 2 Synthesis of Ester-Substituted Phosphorus Curing Agents(“DIA”)

Two exemplary ester-substituted phosphorus curing agents (Example DIA 1and Example DIA 2) were prepared using the DMP 1 from Example 1 inaccordance with aspects of the invention.

Example DIA 1

Example DIA 1 was prepared by reacting 285.5 g of DMP 1 from Example 1(0.66 mol) with 156.5 g of acetic anhydride (1.53 mol) and 55.4 g ofisophthalic acid (IPA) (0.33 mol). During the reactions, the temperaturewas increased to 140° C. and held for 2.5 hrs. The temperature was thenincreased to 250° C. to distill off the acetic acid, which was a productof the reaction of the acetic anhydride, while a vacuum was applied at10 torr for 30 minutes (“mins”). The nitrogen was evacuated at atemperature of 250° C. to obtain Example DIA 1, an ester-substitutedphosphorus-containing bisphenol compound. The amount of acetic acidremoved by distillation was 133.47 grams, which was 95% of thetheoretical amount. The glass transition temperature of theabove-mentioned Example DIA 1 was 128° C., and FI=IR analysis hadobvious C═O absorption at 1742.7 cm-1.

Example DIA 2

Example DIA 2 was prepared by reacting 214.21 g of DMP 1 (0.5 mol) with117.4 g of acetic anhydride (1.15 mol) and 73.93 g of isophthalic acid(0.445 mol). During the reactions, the temperature was increased to 140°C. and held for 2.5 hrs. The temperature was then increased to 250° C.to distill off the acetic acid while a vacuum was applied at 10 torr for30 mins. The nitrogen was evacuated at a temperature of 250° C. toobtain Example DIA 2. The amount of acetic acid removed by distillationwas 122.27 grams, which was 95% of the theoretical amount. The glasstransition temperature of Example DIA 2 was 170° C., and FI=IR analysishad obvious C═O absorption at 1742.7 cm-1.

Comparative Example DIA 1

A comparative example of an ester-substituted phosphorus curing agent(Comparative Example DIA 1) was prepared from DMP 1. Specifically,214.21 g of DMP1 (0.5 mol) was reacted with 117.4 g of acetic anhydride(1.15 mol) and 74.76 g of isophthalic acid (0.45 mol). The temperaturewas increased, during the reactions, to 140° C. and held for 2.5 hrs.The temperature was subsequently increased to 250° C. to distill offacetic acid, and a vacuum of 10 torr was applied for 30 mins. Thenitrogen was evacuated at a temperature of 250° C. to obtain ComparativeExample DIA 1. The amount of acetic acid removed by distillation was122.85 grams, which was 95% of the theoretical amount. The glasstransition temperature of Comparative Example DIA 1 was 179° C., andFI=IR analysis has obvious C═O absorption at 1742.7 cm-1.

Table 1 compares some of the relevant characteristics of Example DIA 1and 2 to Comparative Example DIA 1.

TABLE 1 Ex. DIA 1 Ex. DIA 2 Comp. Ex. DIA 1 DMP:IPA (mol %) 2:1 10:8.910:9 Repeating unit 2 9 10 (w value) Processability v v x

Processability was determined by dissolving the respective DIA in 40 wt.% MEK, subsequently stirring and heating until the solvent is refluxed(80° C. BP), and then cooled to room temperature, and left to standovernight. A “v” value was given if no precipitate was observed. A “x”value was given if precipitate was observed at the bottom. The repeatingunit (“w”) was determined by analyzing the molecular weight using GPCand dividing by the molecular weight of the repeating unit to obtain arepeating unit value.

Example 3 Preparation of Laminated Composite Structure

Epoxy impregnated glass fiber fabrics were produced by impregnatingglass fiber fabric (GF-7628) with an epoxy resin and curing it withExample DIA 1 and/or PF8110M60. 2-Methylimidazole (“2MI”), 10% dissolvedin methanol, was used as a catalyst for curing the epoxy resin.PF8110M60 is a curing agent manufactured by Chang Chun Plastic Co.,Ltd., Taiwan, R.O.C, and distributed under the product number PF8110M60.PF8110M60 is a phenolic resin having an active hydrogen equivalentweight of 100-110 g/equivalent weight. BNE200A is an epoxy resinmanufactured by Chang Chun Plastic Co., Ltd., Taiwan, R.O.C. BEP330A isan epoxy resin manufactured by Chang Chun Plastic Co., Ltd., Taiwan,R.O.C.

Table 2, provided below, shows the epoxy resin and curing agent used foreach epoxy impregnated glass fiber fabric of Examples A-D andComparative Example E.

TABLE 2 Comp. Grams Ex. A Ex. B Ex. C Ex. D Ex. E Epoxy resin BNE200A100 75 50 50 BEP330A 317.1 Curing agent DIA 178.5 178.5 178.5 178.5PF8110M60 39.5 98.7 Catalyst 2MI 0.07 0.06 0.05 0.07 0.11

The cured epoxy impregnated glass fiber fabrics were dried at atemperature of 160° C. to form prepregs. Pieces of each of the prepregswere layered with a sheet of copper foil to form a composite structurehaving a thickness of 2 mm. The composite structure had a single layerof prepreg with two sheets of copper foil adjacent to each side of theprepreg, such that the prepreg was positioned between the two sheets ofcopper foil. The composite structure was laminated at a temperature of210° C. under a pressure of 25 kg/cm². The resulting laminated compositestructures contained the phosphorus-containing epoxy resin and glassfiber fabric.

The laminated composite structures were evaluated and their propertiesare provided in Table 3 below.

TABLE 3 Comp. Ex. A Ex. B Ex. C Ex. D Ex. E Dk(10 GHz) 4.48 4.30 4.414.30 4.71 DF(10 GHz) 0.010 0.0097 0.0101 0.0109 0.025 Tg° C. 186.83184.36 172.45 200.8 151.6

The laminated composite formed of two sheets of copper foil were etchedand the dielectric constant (Dk) and dissipation factor (Df) of weremeasured according to IPC-TM-650-2.5.5.13. The glass transitiontemperature (T_(g)) was measured according to IPC-TM-650-2.4.25 by usingdifferential scanning calorimetry (DSC) (Scan Rate: 20° C./min.) and aspecimen that was prepared by retrieving 10 mg of resin composition fromthe prepreg. Typically, it is desirable for epoxy compositions having aDMP structure to have a glass transition temperature of lager than 150°.It was particularly surprising that the cured epoxy resin of laminatecomposite structure Ex. D exhibited a glass transition temperature ofgreater than 200° C.

Example 4 Preparation of Laminated Composite Structure

Epoxy impregnated glass fiber fabrics (Example F and Comparative ExampleG) were produced by impregnating glass fiber fabric (GF-7628) with anepoxy resin and curing it with Example DIA 1, PF8110M60. As noted above,PF8110M60 is a curing agent manufactured by Chang Chun Plastic Co.,Ltd., Taiwan, R.O.C. BNE200A is an epoxy resin manufactured by ChangChun Plastic Co., Ltd., Taiwan, R.O.C. BE504EM is an epoxy manufacturedby Chang Chun Plastic Co., Ltd., Taiwan, R.O.C.

The phosphorus content was determined for the cured epoxy resins.Specifically, a standard curve of UV-Vis absorption at 420 nm wasprepared from a set of potassium dihydrogen phosphate solutions atvarious concentrations. Sulfuric acid and potassium persulfate wereadded into epoxy resin samples. Following a digestion process carriedout under a temperature of 100° C. for 60 mins, the digested samplesolutions were treated with molybdovanadate reagent to formvanadomolybdophosphoric acid. The samples were measured by UV-Visabsorption at 420 nm. The phosphorus content was determined from thestandard curve in mass %.

Table 4, provided below, shows the epoxy resin and curing agent used foreach epoxy impregnated glass fiber fabric.

TABLE 4 Grams (“g”) Ex. F Comp. Ex. G Epoxy resin BNE200A 200 BNE200A200 BE504EM 20 BE504EM 16 Curing agent Example DIA 1 178.4 DOPO 111.3PF8110M60 39.5 PF8110M60 80 Phosphorus content % 2.3% 2.5%

The cured epoxy impregnated glass fiber fabrics were dried at atemperature of 160° C. to form prepregs. Five pieces of the prepregswere layered and a sheet of 35 μm copper foil was placed on the top andbottom of the stack of five pieces of prepreg. This structure waslaminated at a temperature of 210° C. under a pressure of 25 kg/cm². Thelaminated composite structures contained the phosphorus-containing epoxyresin and glass fiber fabric.

The laminated composite structures of Example F and Comparative ExampleG were evaluated and their properties are summarized in Table 5.

TABLE 5 Ex. F Comp. Ex. G Dk[1 MHz] 4.30 4.93 Df[1 MHz] 0.011 0.012Flame retardancy V0 V0 Tg(° C.) 201 189 Td(° C.) 395 380 Heat resistanceS-288 >180 >180

The laminated composite formed of two sheets of copper foil were etchedand the Dielectric Constant (Dk) and Dissipation Factor (Df) weremeasured according to IPC-TM-650-2.5.5.9 at 1 MHz. The flame retardancywas measured according to UL94. A V0 rating means that burning stopswithin 10 seconds after two applications of ten seconds each of a flameto a test bar, with NO flaming drips being allowed. The glass transitiontemperature (T_(g)) was measured according to IPC-TM-650-2.4.25 by usingDifferential Scanning calorimetry (DSC) (Scan Rate: 20° C./min.) and aspecimen that was prepared by retrieving 10 mg resin of composition fromthe prepreg. The decomposition temperature (“Td”) (5% weight loss) wasmeasured according to IPC-TM-650-2.3.40 using a thermogravimetricanalyzer (TGA) at a scan rate of 10° C./min. The thermal stability(“S-288”), referred to above as heat resistance, was measured accordingto JIS-C-6481. Specifically, the laminated entity was immersed into a288° C. solder furnace and the time to delamination measured.

Example 5 Preparation of Cured Epoxy Resin

An epoxy resin was cured using Example DIA 1. BNE200A is an epoxy resinmanufactured by Chang Chun Plastic Co., Ltd., Taiwan, R.O.C.2-Methylimidazole (“2MI”), 10% dissolved in methanol, was used as acatalyst for curing the epoxy resin. The cured epoxy resin of Example Hwas cured for 2 hrs at a temperature of 210° C.

The cured epoxy resin of Example H was assessed to determine variouscharacteristics. The Dielectric Constant (Dk) and Dissipation Factor(Df) were measured according to IPC-TM-650-2.5.5.13 at 5 GHz and 10 GHz.The composition of the epoxy resin as well as the dielectric constantand dissipation factor of the cured epoxy resin are summarized in Table6.

TABLE 6 Ex. H Epoxy (g) BNE200A 100 Curing agent (g) Ex. DIA 1 178.5Catalyst (g) 2MI 0.07 DK(5 GHz) 3.15 DF(5 GHz) 0.010 DK(10 GHz) 3.02DF(10 GHz) 0.014

What is claimed is:
 1. A phosphorus containing compound of formula (I):

wherein, X is an aromatic hydrocarbon group having 6 to 30 carbon atomsor a bivalent linear or branched alkylene group of 1 to 8 carbon atoms,R^(A) is selected from an alkyl group having 1 to 6 carbon atoms, aphenyl group, a napthyl group, and an aromatic phenol group, w is aninteger of 1 to 9, R₁, R₂, R₃, and R₄ are independently selected from H,C₁-C₁₀ alkyl, C₁-C₁₀ alkoxy, and C₃-C₁₀ cycloalkyl, R₅ is selected fromthe group consisting of C₁-C₁₀ alkyl, C₁-C₁₀ alkoxy, C₃-C₁₀ cycloalkyl,and Ar₃, and Ar₁ and Ar₂ are independently selected from the followingstructure:

wherein Ar₃ is selected from the following structures:

wherein: R₆ and R₇ are independently selected from the group consistingof H, C₁-C₁₀ alkyl group, C₁-C₁₀ alkoxy, and a cyclic alkyl group having3-10 carbon atoms, m and n are independently an integer from 0 to 3, andm plus n is less than 5, R₈ is absent or is selected from the groupconsisting of —CH₂—, —(CH₃)₂C—, —CO—, —SO₂—, and —O—, and R₉ is absentor is —(CH₂)p, wherein p is an integer from 1 to 20, and z is
 1. 2. Thephosphorus containing compound of claim 1, wherein: R₁, R₂, R₃, and R₄are H, and R₅ is a methyl.
 3. The phosphorus containing compound ofclaim 1, wherein X is an aromatic hydrocarbon group having 6 to 10carbon atoms.
 4. The phosphorus containing compound of claim 3, whereinX is an aromatic hydrocarbon group having 6 to 8 carbon atoms.
 5. Thephosphorus containing compound of claim 1, wherein X is an unsubstitutedaromatic hydrocarbon group having 6 to 30 carbon atoms.
 6. Thephosphorus containing compound of claim 1, wherein R^(A) is an aromaticphenol group selected from a phenol group, an o-cresol group, anm-cresol group, a p-cresol group, or a 1-naphthol group.
 7. Thephosphorus containing compound of claim 1, wherein R^(A) is an alkylgroup having 1-4 carbon atoms.
 8. The phosphorus containing compound ofclaim 7, wherein R^(A) is an alkyl group having 1 or 2 carbon atoms. 9.The phosphorus containing compound of claim 1, wherein R^(A) is anunsubstituted alkyl group having 1 to 6 carbon atoms.
 10. The phosphoruscontaining compound of claim 1, wherein R₁, R₂, R₃, and R₄ are H, R₅ isa methyl, X is an unsubstituted aromatic hydrocarbon group having 6 to30 carbon atoms, and R^(A) is an alkyl group having 1 to 6 carbon atoms.11. A cured epoxy resin comprising: (a) an epoxy; and (b) the phosphoruscontaining compound of claim
 1. 12. The cured epoxy resin of claim 11having a glass transition temperature of greater than 180° C.
 13. Thecured epoxy resin of claim 12, wherein the glass transition temperatureis 200° C. or more.
 14. The cured epoxy resin of claim 11 having adielectric constant of 3.0 or less as measured according toIPC-TM-650-2.5.5.13 at 10 GHz.
 15. The cured epoxy resin of claim 11having a dissipation factor of 0.014 or less as measured according toIPC-TM-650-2.5.5.13 at 10 GHz.
 16. A laminate composite structurecomprising: (a) a glass fiber fabric, (b) an epoxy, (c) a copper foil,and (d) a phosphorus containing compound according to formula (I):

wherein, X is an aromatic hydrocarbon group having 6 to 30 carbon atomsor a bivalent linear or branched alkylene group of 1 to 8 carbon atoms,R^(A) is selected from an alkyl group having 1 to 6 carbon atoms, aphenyl group, a napthyl group, and an aromatic phenol group, w is aninteger of 1 to 9, R₁, R₂, R₃, and R₄ are independently selected from H,C₁-C₁₀ alkyl, C₁-C₁₀ alkoxy, and C₃-C₁₀ cycloalkyl, R₅ is selected fromthe group consisting of C₁-C₁₀ alkyl, C₁-C₁₀ alkoxy, C₃-C₁₀ cycloalkyl,and Ar₃, and Ar₁ and Ar₂ are independently selected from the followingstructure:

wherein Ar₃ is selected from the following structures:

wherein: R₆ and R₇ are independently selected from the group consistingof H, C₁-C₁₀ alkyl group, C₁-C₁₀ alkoxy, and a cyclic alkyl group having3-10 carbon atoms, m and n are independently an integer from 0 to 3, andm plus n is less than 5, R₈ is absent or is selected from the groupconsisting of —CH₂—, —(CH₃)₂C—, —CO—, —SO₂—, and —O—, and R₉ is absentor is —(CH₂)p, wherein p is an integer from 1 to 20, and z is
 1. 17. Thelaminate composite structure of claim 16, wherein R^(A) is an alkylgroup having 1 to 6 carbon atoms, R₁, R₂, R₃, and R₄ are H, and R₅ is amethyl.
 18. The laminate composite structure of claim 16, wherein R₁,R₂, R₃, and R₄ are H, R₅ is a methyl, X is an unsubstituted aromatichydrocarbon group having 6 to 30 carbon atoms, and R^(A) is an alkylgroup having 1 to 6 carbon atoms.
 19. The laminate composite structureof claim 16 having a dielectric constant of 4.6 or less as measuredaccording to IPC-TM-650-2.5.5.13 at 10 GHz.
 20. The laminate compositestructure of claim 16 having a dissipation factor of 0.015 or less asmeasured according to IPC-TM-650-2.5.5.13 at 10 GHz.